Referring to FIG. 1, a conventional turning light lamp is mounted on the outer side of a headlight 11 which acts as a main illumination source of a vehicle and which has an optical axis extending in a front-rear direction. The conventional turning light lamp includes a curved reflector 12, and a halogen bulb 13 disposed with respect to the reflector 12. Such a turning light lamp can provide illumination in addition to the illumination provided by the headlight 11 while the vehicle is turning, such that the vehicle turning safety can be enhanced. However, the above-mentioned turning light lamp is bulky and provides only single-segment lighting.